Certain test apparatus associated with computer interface equipment requires the positioning of individual test adapters into receivers with multiple contacts of the test adapter operatively engaged in current carrying relationship with coacting contacts of the receiver. The receiver may accept one or more individual test adapters. The present invention embraces a receiver cam actuating mechanism of high efficiency, compactness and convenience of operation for imparting a required movement to a roll cam bar which moves against the concave surface of a juxtaposed individual test adapter to override accumulated forces created by the deflection of flexible contacts resisting engagement with test adapter contacts.
Since pairs of such contacts resist engagement by a force in the range of 6 ozs. to 8 ozs., and the test adapter and receiver have as many as 6000 pairs of coacting contacts, it is possible to encounter a total resistive force of 3000 pounds, more or less, which must be overridden by the action of the receiver roll cam bar. The individual test adapter normally nests ball detent type contacts and the receiver nests yielding paddle type contacts. It is the individual test adapter which comprises the moving component actuated by the receiver roll cam bar, and wherein the ball detent contacts are fixed post elements which cause deflection of the receiver paddle contacts as engagement takes place.
Individual test adapters of the type involved in this invention are placed within and removed from receivers for interchange of programming using other individual test adapters or for repair. The receiver is installed in a recess or well in a table top of desk design. Operators working on these units are usually women seated at the provided table and it becomes important that they are able to interchange the individual test adapters with relative ease, convenience and efficiency. To achieve these ends, it is imperative that the receiver roll cam bar be able to override opposing forces after a minimum amount of movement of the mechanism hand lever which extends below the table top in ready reach of the operator and with minimum effort on the part of the operator. The roll cam bar driving or operating mechanism forming the heart of this invention completely accomplishes these stated requirements in a simple and comparatively economical manner as will be fully described hereinafter.
The mechanism includes a number of stacked components which in assembled relationship are snugly received in a recess provided in one frame side of the receiver, whereby the presence of the mechanism does not increase the overall dimensions of the receiver frame. The mechanism is rugged and durable and its stacked interconnected linkage components are self-retaining in the assembly and are captured between a single retainer ring and an opposing wall of the mounting recess provided in the receiver side rail or frame member. Among the important advantages of the invention are the following:
(1) Hand lever movement of less than 6 inches produces roll cam bar rotation for a full 90 degrees.
(2) The mechanism is positively stopped in both the closed and open positions by abutment with a wall of the receiver frame mounting recess to prevent mechanism "override" in either position.
(3) The hand lever is located outwardly of the receiver and at the outside of the stacked linkage where a single E-ring is employed to maintain the mechanism assembled with the receiver and roll cam bar.
(4) The mechanism is nested inside of the receiver frame margin and therefore does not increase the size of the receiver.
Other features and advantages of the invention will become apparent during the course of the following description.
The following known prior art United States patents of general interest only relative to the invention are made of record under 37 C.F.R. 1.56:
8,597 304,048 PA1 63,945 705,701 PA1 164,212 2,612,058 PA1 191,087 2,782,666